From Our Idiot Brother to Parks & Rec, Kathryn Hahn has turned in some pretty genius supporting performances. This month, however, finds her not only grabbing Jennifer Aniston’s tatas in the pot comedy We’re the Millers, but also (finally!) getting top billing with Afternoon Delight. In it, she plays Rachel, a stay-at-home mom in a sexless marriage who takes in a stripper, McKenna (Juno Temple), with hopes of saving her. It pans out about as well as you’d expect.

I read you were Sally Bowles in a production of Cabaret when you were at Yale.

I was! It was real low-budge -- a lot of Duane Reade fishnets -- but it was heaven. I’d never been the ingénue. I was usually “The Man” or “Grandma.”

And you were cast as Eddy in the American version of Ab Fab, which, sadly, never aired.

Zosia Mamet (Girls) was going to be Saffy; Kristen Johnston was perfect as Patsy. It had a crazy-good pedigree, but bad timing: People didn’t want to joke about reckless spending [in 2009].

But we will see you in We’re the Millers.

Yes, in Step-Ups, with a fanny pack and a visor, as part of an American couple who love to travel in their RV over the holidays. I loved it.

In Afternoon Delight you get a lap dance from a chick. Do women really do this?

Absolutely. I went with my husband once. We’d gone to see Kill Bill and he was like, “Do you want to?” and I was like, “What the hell?”

So you channeled your own experience.

I love that scene because it’s mysterious. Rachel is captured by something in this young angel -- she smells like a cupcake. Rachel wants to save her, fuck her, be her. Of course, McKenna’s job is to make you feel like you’re the only person in the world... I’m quoting a Rihanna song now.

But later, things get weird when McKenna hops onto your bed and gives you a massage with Vicks VapoRub.

I didn’t see that scene as sexual at all -- I think it was more of a profound energy exchange. There’s something about it that cracks Rachel open.

And clears out her sinuses.

Exactly.

It's funny that you don't see the scene as sexual. I think the movie in general has all the ingredients to become a lesbian cult favorite. One writer said that Rachel has this "sexy, low femme vibe."

Oh my god, I love that! I'm going to tattoo that on my arm. Yes, that's absolutely in there. We had shot a kiss scene, but it didn't end up in the movie. One night, late at night, Rachel was digging through the medicine cabinet, and McKenna comes in, and it ends up becoming real intimate. I think Jill [Soloway, the director] handled it well, but we didn't want the story to be strictly about that. It's in there, but we didn't want it to be, like, a lovers' breakup. We decided we wanted to open it up more. But I always thought that they do fall in love, just not in a strictly sexual relationship where they want to be together and run off into the sunset.

One of my favorite scenes is where Rachel attends her friend's "Women Who Wine" party and has, well, basically a drunken meltdown. Was that all improvised?

I love that scene. They set up cameras and we basically improvised, but parts of Rachel's bit were not. Her talking about her college experience and her abortion were in the script. She definitely has a breakdown. This particular group of women are all moms. They have a specific life they're leading in a very hip Southern California neighborhood, and they break it down. It's fascinating. We shot that scene during the day in this amazing house, and they blacked out the curtains and gave us fake red wine, and when we emerged at 5 p.m. in the blinding L.A. light, we were like, "What just happened? That was so crazy."

You play drunk so believably.

Well, I have a lot of experience.

I love that during your breakdown you freak out about iCloud. "The Cloud! What is the Cloud?!"

Rachel never feels like she's "in" with these moms, and that's the beginning of the end for her. She blows it all. It's pretty amazing for somebody who's so concerned with her place in the social world and her house and having the perfect child and the right school to just blow it. She needed to explode to find herself.

Are you on the Cloud?

Oh, honey, I've got a Blackberry and a Filofax. I still get my photos from Kodak. I don't really even understand the cloud. It makes me nervous.

At the "Women Who Wine" party you girls not only talk openly and lightly about abortion, you also talk about jerking off to the rape scene in The Accused. That's racy.

Yes, masturbating to The Accused. I mean, it's so intense. I think it was such an incredible movie, and it was an awful, awful thing that happened, but I think the metaphor, why these women are talking about it, is like the idea of losing control. It's a turn-on for these ladies: being out of control.

Did you have hesitations about going there?

Yes, absolutely. I don't think any of us are condoning rape or abortion. No one was saying, "This is what every woman dreams of: getting raped." It was awful, awful, awful, but these ladies are a particular group of women, and they're unhinged by alcohol, and these things come out of their mouths. These things just fall out, and you wish you could take them back, but you can't, and now they're in the middle of a party.

Some of your best recent characters -- Janet in Our Idiot Brother and cutthroat campaign manager Jennifer Barkley on Parks and Recreation -- have been total psycho bitches. But you seem pretty friendly.

It's incredibly freeing to be able to do that on camera, because that's just not who I am in real life at all. I wish I had a little more Jennifer Barkley in me. Honestly, I do.

I mean, your role in Parks and Recreation is sort of a gay man's dream. You got to be Paul Rudd's right-hand lady and you got to shag Rob Lowe.

I know, exactly. It was really exciting. My husband is thrilled about it.